The Sonoma-Marin Area Rail Transit system will officially launch with a train at 12:49 p.m. from the Sonoma County Airport Station south to downtown San Rafael with eight stops in between. SMART will host an opening event at 9 a.m. Friday at its downtown Santa Rosa Station, 7 Fourth St., at Railroad Square. Reporter @MarkPradoIJ posts live. Join the conversation on Twitter with #SMARTtrain. Follow on your mobile device.